The story is set against the backdrop of South Africa's diamond mining industry, which experienced rapid growth and accompanying challenges in the late 19th century. "I.D.B." stands for "Illicit Diamond Buying," a major problem in the diamond fields where unauthorized individuals would buy and sell diamonds outside the control of the official mining companies and government regulations.The novel likely explores the adventures and moral dilemmas of its characters involved in or affected by the illicit diamond trade. Through its narrative, Sheldon probably addresses themes of greed, deception, and the socioeconomic impacts of the diamond rush on both the local population and the adventurers who flocked to the region seeking fortune.Louise Vescelius Sheldon was known for her ability to weave social commentary into her stories, and "An I.D.B. in South Africa" is no exception. The book provides a fascinating look into a turbulent time in South Africa's history, offering insights into the human condition and societal challenges through the lens of adventure and intrigue.